as the tech guys told us, this will happen to each server in the near future. Right after the end game, the server shuts down the game, and - here is the bug - will not create a link on the lobby page (so you cannot log in again). Untill that bug is fixed, they will set up the lobby and logon link manually ... and they need some time for that, so you can log in again after a short time.They are working on a permanent fix.

That's a free translation of what Saphirus told us in a different thread.